Ignition device



Feb. 23, 1965 c, MELAND 3,171,046

IGNITION DEVICE Filed June 25. 1960 INVENTOR. REIGHTON B. HELAND BY 013W HLS ATTORNEY United States Patent M 3,171,046 IGNITION DEVECE Creighton R. Meland, Dayton, Ohio, assignor to General Motors Corporation, Detroit, Mich, a corporation of Delaware Filed lane 23, 1960, Ser. No. 38,378 Claims. (Cl. 3il7--l5) This invention relates to ignition equipment and more particularly to a combined ignition coil and transistor control unit for applying spark impulses to the spark plugs of an internal combustion engine.

The present invention is directed to a combined ignition coil and transistor control unit that may be substituted for the ignition coil presently being used in the ignition systems of internal combustion engines. When such a substitution is made, the transistor control unit, which includes at least one transistor, controls the current flow through the primary winding of the ignition coil in response to opening and closing of the breaker contacts of the ignition system. The current flow through the breaker points is small as compared to conventional ignition systems and better sparking characteristics are achieved When the ignition device of this invention is used.

One of the objects of this invention is to provide a com-- bined ignition coil and transistor control unit for an ignition system wherein the control unit is supported by the ignition coil and is electrically connected with at least one of the windings of the ignition coil.

Another object of this invention is to provide a combined ignition coil and transistor control unit wherein the control unit is supported by the terminals of the ignition coil which also serve to electrically connect the control unit with at least one winding of the ignition coil.

Still a further object of this invention is to provide a combined ignition coil and transistor control unit wherein the control unit includes a metal heat sink member that supports a transistor and wherein this heat sink member is supported directly by the ignition coil.

A further object of this invention is to provide a combined ignition coil and transistor control unit wherein the transistor control unit includes a metal heat sink member that carries a transistor and wherein this heat sink member is supported by and electrically connected to one of the terminals of the ignition coil and provides an electrical connection between the collector electrode of the transistor and the one terminal of the ignition coil.

Another object of this invention is to provide a transistor control unit that may be applied to existing ignition coils by simply fitting the control unit to an ignition coil, the control unit having the required openings and electrical connections for application to existing ignition systems.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein preferred embodiments of the present invention are clearly shown.

In the drawings:

FIGURE 1 is a plan view of a combined ignition coil and transistor control unit made in accordance with this invention.

FIGURE 2 is a view looking in the direction of arrow 2 of a combined ignition coil and transistor control unit made in accordance with this invention.

FIGURE 3 is a view looking in the direction of the arrow designated by reference numeral 3 in FIGURE 1.

FIGURE 4 is a modified combined ignition coil and transistor control unit made in accordance with this invention.

FIGURE 5 is a schematic electrical circuit diagram illustrating the application of the combined ignition coil 3,1?1 ,045 Patented Feb. 23, 1965 and transistor control unit of this invention to an internal combustion ignition system.

Referring now to the drawings and more particularly to FIGURE 1, the reference numeral It) generally designates a conventional ignition coil having a container or housing portion formed of metal material which houses the internal parts of the ignition coil. The ignition coil 10 has a cap generally designated by reference numeral 14 which is formed of insulating material and which has an upwardly projecting portion 16 containing the center electrode of the ignition coil which is designated by reference numeral 18. The can or container portion 12 contains a primary winding 2i? and a secondary winding 22 which are not illustrated in FIGURE 1 but which are shown in the schematic diagram of FIGURE 5. The primary windings 20 and 22 are tied together at one end and are connected with the terminal stud designated by reference numeral 24 in FlGURE 1. This terminal stud is shown schematically in FIGURE 5.

The opposite side of the secondary winding 22 is connected with the center electrode 18 of the ignition coil as in conventional practice. The opposite end of primary winding 20 of the ignition coil is connected with the terminal stud 26 which is also illustrated schematically in FIGURE 5. The terminal studs 24 and 26 have external threads as is clearly evident from an inspection of FIG- URE 1.

The ignition coil 10 carries a transistor control unit which is generally designated by reference numeral 30. The transistor control unit 30 includes a metal heat sink member 32 which is preferably formed of aluminum material which carries a power transistor 34. This heat sink member dissipates the heat generated in transistor 34 when the ignition system is in operation. The transistor 34 has an emitter electrode 36 which passes through an opening in the heat sink member 32 and which is insulated therefrom by insulating material 38. The transistor 34 has a base electrode 40 which likewise passes through an opening in the heat sink member 32 and is insulated therefrom by the insulating material 44. The transistor 34 is of the type wherein the case or enclosure of the transistor is the collector electrode thereof and it thus is seen that since the case is mounted directly on the heat sink member 32, the collector electrode of transistor 34 is connected directly to the heat sink member 32.

The transistor 34 is fixed to the heat sink member 32 by the screw fasteners 46 which are threaded directly into the heat sink member 32. The case of the transistor is formed with an additional opening 48 that is adapted to receive the terminal stud 26 of the ignition coil when the transistor control unit is assembled to the ignition coil. This opening 48 in the transistor case or housing is not required and only provides additional support for the transistor when the transistor control unit is fixed to the ignition coil.

The heat sink member 32 carries terminals 50 and 52 which are insulated from the heat sink member 32 by a sheet of insulating material 54. The terminal 50 carries a screw fastener 55 whereas the terminal 52 carries a screw fastener 56, both of these fasteners being used for securing lead wires to the terminals. It is seen that a pair of resistors 53 and are provided, one end of the resistor 538 being connected with terminal 5t and one end of the resistor 6d being connected with the terminal 52. The opposite ends of the resistors 58 and 60 are connected together by a rivet or other terminal stud s2 and it is seen that the base electrode 40 is likewise connected to toe junction point 62. T he emitter electrode 36 is connected to terminal 52. The terminals 50 and 52 and the resistors 58 and 60 are all supported by and insulated from the heat sink member 32. It will be appreciated that this securing is accomplished by suitable rivets that support the elements just described but which are insulated from the heat sink member 32.

The heat sink member 32 has an opening 64 which receives the insulator member 66. In addition, this heat sink member 32 is formed with a central opening 68 which has a configuration that receives the cap or top end 14 of the ignition coil. This opening 68 is cast to shape to receive a cap of the ignition coil to which the transistor control unit is to be applied. In other words, a snug fit will be achieved between the heat sink member 32 and the top or cap end of the ignition coil when the transistor control unit is fitted to the ignition coil 10. It can be seen from FIGURE 1 that the heat sink member 32 in addition to the openings 64 and 68 has a noninsulated opening 70 which is adapted to receive the terminal stud 26 of the ignition coil.

It can be seen from FIGURE 1 that the control unit 30 is simply assembled to the ignition coil by slipping the heat sink member onto the ignition coil with the terminal studs 24 and 26 passing respectively through the insulator member 64 and the opening 70 and with the upstanding portion 16 of the ignition coil cap passing through the opening 68 formed in the heat sink member 32. The heat sink member, and thus the transistor control unit are then held in place by the nuts 72 and 74 which are threaded onto the studs 24 and 26.

In the embodiment shown in FIGURE 1, the terminal stud 26 passes through the opening 48 formed in the case of transistor 34 but this is not necessary, it being apparent that the lock washer below nut 74 could directly contact the heat sink member 32 with the transistor being secured in place only by the screw fasteners 46. It will be apparent that the combined unit of FIG- URE 1 may be marketed as a unit or the transistor control unit 30 might be separately marketed to be applied to ignition coils presently in operation in internal combustion ignition systems.

Referring now more particularly to FIGURE 5, a schematic circuit diagram of an internal combustion ignition system is illustrated employing the combined ignition coil and transistor control unit of this invention. In FIGURE 5, as far as possible the same reference numerals have been used as were used in FIGURES 1 through 3 to designate identical parts in these figures. In the ignition system of FIGURE 5, the reference numeral 80 is used to designate a source of direct current power which in this case is a storage battery. It can be seen that one side of the storage battery 80 is connected directly to ground whereas the opposite side of the battery is connected with the ignition switch 82. The opposite side of the ignition switch 8.2 is connected With the terminal 52 of the transistor control unit by a suitable lead wire.

In FIGURE 5, the reference numeral 84 designates a set of breaker contacts which are opened and closed by a cam member 86 driven in synchronism with the internal combustion engine. It can be seen that one side of the breaker points 84 are connected directly to ground whereas the opposite side of the breaker points and thus the movable breaker lever 87 are connected by a lead Wire 88 to the terminal 50 of the transistor control unit. The collector electrode of the transistor 34 which is designated by reference numeral 90' in FIGURE 5 is connected to the terminal 26 and thus to the primary winding of the ignition coil by virtue of it being mounted directly on the heat sink member 32. The center electrode 18, which is connected with the secondary winding 22 of the ignition coil, is connected with a conventional rotor contact 92 cooperating with contacts carried by a distributor cap 94. Contacts on the distributor cap 94 are connected with spark plugs, one of which is designated by reference numeral 96. The terminal stud 24 of the ignition coil must be connected to ground by some suitable lead wire.

In the operation of the ignition system illustrated in FIGURE 5, when the breaker contacts are closed, a base circuit is made for the transistor 34 through resistor 58 and the closed breaker contact 84. This causes current to flow between the emitter 36 and collector of the transistor and through the primary Winding 20 of the ignition coil to ground. When the breaker points 84 open, the base circuit for transistor 34 is likewise opened so that there is no emitter to base current. This cuts off the emitter to collector current of transistor 34 and thus cuts off the current flow to the primary winding 20 of the ignition coil. This causes a high voltage to be induced and the secondary winding 22 which is applied through the rotor contact 92 and distributor cap contacts to the spark plugs 96.

Referring now more particularly to FIGURE 4, a modified combined ignition coil and transistor control unit is illustrated wherein the heat sink member is spaced somewhat from the ignition coil so that the heat generated by the ignition coil will have less effect on heating of the heat sink unit. In FIGURE 4, the same reference numerals as were used in FIGURE 1 have been employed to identify identical parts. In FIGURE 4, the terminal stud 26a in contrast to terminal stud 26 of FIGURE 1 is formed with a ledge portion 26b whereas the terminal stud 24a is likewise formed with a ledge portion 2412. These ledge portions are contacted by the heat sink member 32 and it is thus seen that the heat sink member is spaced away from the top or cap 14 of the ignition coil 10. In this manner, there is less heat transfer between the ignition coil and the heat sink member 32, it of course being understood that the purpose of the heat sink member 32 is to dissipate heat generated by the transistor 34, which is also the case in FIGURE 1. In FIGURE 4, the heat sink member 32 is again provided with a suitable opening or recess for reception of the upstanding portion 16 of the ignition coil. The FIGURE 4 embodiment may be used with the ignition circuit of FIGURE 5 and its operation is identical with the embodiment illustrated in FIGURES 1 through 3.

It will be apparent from the foregoing that a combined ignition coil and transistor control unit has been provided which may be assembled as a unit in a motor vehicle to form a component part of an internal combustion ignition system. It will also be apparent that the control unit might be marketed without the ignition coil 10 and might be applied to the ignition coils being used in motor vehicles by simply securing the control unit to an existing ignition coil. It will also be observed that the control unit provides for eflicient heat dissipation for the transistor 34 and also provides simple and direct electrical connections between the transistor and the ignition coil as well as providing terminals which are readily connected to lead wires already available in motor vehicle internal combustion engine ignition systems.

While the embodiments of the present invention as herein disclosed constitute a preferred form, it is to be understood that other forms might be adopted.

What is claimed is as follows:

1. An ignition control unit comprising, an ignition transformer having a housing, a primary winding and a secondary winding located within said housing, one end of said housing being formed of insulating material, a terminal stud passing through said end of said ignition transformer and projecting beyond said insulating material, said terminal stud being connected with said primary Winding, a metal heat sink having an opening receiving said terminal stud, fastener means engaging said termlnal stud and clamping said metal heat sink between the end of said ignition transformer housing that is formed of insulating material and said fastener means,

said metal heat sink being electrically connected with said terminal stud, and a three terminal semiconductor supported by said metal heat sink, one terminal of said semiconductor being in direct metal to metal contact with said heat sink member whereby said heat sink memher is electrically and thermally connected with said terminal stud.

2. In combination, an ignition transformer having a housing one end of which is formed of insulating material, said housing enclosing a primary winding and a secondary winding, a terminal stud passing through said insulating material and electrically connected with said primary winding, a metal heat sink having an opening receiving a projecting portion of said terminal stud, fastener means clamping said metal heat sink between it and the end of said housing that is formed of insulating material and a transistor having an outer metal case which is mounted in direct metal to metal contact with said metal heat sink member, said metal heat sink being electrically connected with said terminal stud of said ignition transformer.

3. An ignition control unit comprising, an ignition transformer having a housing one end of which is formed of insulating material, a primary winding and a secondary winding enclosed by said housing, first and second threaded terminal studs passing through said insulating material, said first terminal stud being electrically connected with said primary winding, a metal heat sink member having openings receiving said first and second projecting terminal studs, said metal heat sink member being clamped between the end of said housing that is formed of insulating material and nut means which engage the threaded terminal studs, said first terminal stud being electrically connected with said metal heat sink and said second terminal stud being electrically insulated from said metal heat sink, and a transistor having an outer metal case supported by said metal heat sink memher, said outer metal case being in direct metal to metal contact with said metal heat sink member whereby said metal heat sink member is thermally and electrically connected with the metal case of said transistor and forms an electrical connection between the metal case of said transistor and said first terminal stud that is connected with said primary winding.

4. An ignition control unit comprising, an ignition transformer having a housing one end of which is formed of insulating material, said housing enclosing a primary winding and a secondary winding, first and second metal terminals projecting through said end of said housing one of which is connected with said primary winding, said terminals including ledge means spaced from said end of said housing, a metal heat sink having openings receiving said terminals and engaging said ledge means, fastener means for clamping said metal heat sink member between the fastener means and said ledge means, one of said terminals being electrically insulated from said metal heat sink member and the other of said terminals being electrically connected with said metal heat sink member, and a three-terminal semiconductor having an outer metal part, said outer metal part being in direct metal to metal contact with said metal heat sink member whereby said outer metal part is electrically and thermally connected with said metal heat sink member, said outer metal part forming one terminal of said three-terminal semiconductor.

5. An ignition controller comprising, an ignition transformer having a housing one end of which is formed of insulating material, a primary winding and a secondary winding enclosed by said housing, an electrode in said insulating material connected with said secondary winding, first and second threaded terminal studs projecting through said insulating material one of which is connected with said primary winding, and an ignition control unit supported by said one end of said ignition transformer, said ignition control unit including a metal heat sink which has an opening receiving one of said terminal studs, fastener means threaded on to said one terminal stud for securing said heat sink in place with respect to said end of said ignition transformer, a three terminal semiconductor supported by said metal heat sink member having one of its terminals connected with the terminal stud of said ignition transformer that is connected with said primary winding, biasing elements for said semiconductor supported by said metal heat sink member, and input terminals for said control unit supported by said metal heat sink member adapted to be connected with a timing device such as breaker contacts.

References Cited in the file of this patent UNITED STATES PATENTS 2,817,048 Thuermal et al. Dec. 17, 1957 2,852,388 Hartman Sept. 16, 1958 2,860,251 Pakswer et a1 Nov. 11, 1958 2,984,774 Race May 16, 1961 FOREIGN PATENTS 1,137,949 France Jan. 21, 1957 

1. AN IGNITION CONTROL UNIT COMPRISING, AN IGNITION TRANSFORMER HAVING A HOUSING, A PRIMARY WINDING AND A SECONDARY WINDING LOCATED WITHIN SAID HOUSING, ONE END OF SAID HOUSING BEING FORMED OF INSULATING MATERIAL, A TERMINAL STUD PASSING THROUGH SAID END OF SAID IGNITION TRANSFORMER AND PROJECTING BEYOND SAID INSULATING MATERIAL, SAID TERMINAL STUD BEING CONNECTED WITH SAID PRIMARY WINDING, A METAL HEAT SINK HAVING AN OPENING RECEIVING SAID TERMINAL STUD, FASTENER MEANS ENGAGING SAID TERMINAL STUD AND CLAMPING SAID METAL HEAT SINK BETWEEN THE END OF SAID IGNITION TRANSFORMER HOUSING THAT IS FORMED OF INSULATING MATERIAL AND SAID FASTENER MEANS, SAID METAL HEAT SINK BEING ELECTRICALLY CONNECTED WITH SAID TERMINAL STUD, AND A THREE TERMINAL SEMICONDUCTOR 